Methods for injecting a drug into prostate tissue

ABSTRACT

Method and surgical instrument for treating prostate tissue including a surgical instrument having a main body, a needle deployment port, a needle, first and second handles and a lockout release mechanism to limit needle extension. Additionally, a kit includes the surgical instrument, together with a cystoscope, and optionally a syringe and reservoir of ethanol. The method includes needle-less injection and visualizing the ethanol injection by delivering both an echogenic agent and ethanol either by needle or needle-less injection or by providing an ultrasonically visible marker near the tip of the ethanol delivery cannula. The method also includes extending the needle transversely of the instrument housing using a link assembly.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of pending U.S. applicationSer. No. 11/148,095, filed Jun. 8, 2005, which is a divisionalapplication of U.S. application Ser. No. 10/269,405, filed Oct. 11,2002, now U.S. Pat. No. 6,905,475, which claims the benefit of U.S.provisional patent application No. 60/329,262, filed Oct. 12, 2001, theentire disclosures of which are incorporated herein by reference for allpurposes.

BACKGROUND OF THE INVENTION

The present invention relates to surgical instruments and methods,particularly those for treating prostate tissue, and to surgical kitsfor use in such methods.

FIG. 1 illustrates the anatomical position of the prostate 10 (includinglateral lobes 15) and adjacent tissue including the seminal vesicles 11,bladder neck 12, and pelvic tissues including sphincter muscles 14.

Prostate disease is a significant health risk for males. Diseases of theprostate include prostatitis, benign prostatic hyperplasia orhypertrophy (BPH) and prostatic carcinoma. Benign prostatic hypertrophyis a very common disorder, affecting an estimated 12 million men in theUnited States alone. BPH is a chronic condition and is strongly agerelated; approximately 50% of men over 50, 75% of men over the age of 70and 90% of men over the age of 80 have BPH.

BPH is treated with a large number of therapeutic modalities.Transurethral resection of the prostate (TURP) is a preferred method oftreating BPH. A typical TURP involves general anesthesia, and theplacement of a resectoscope in the urethra to remove multiple smallchips of hyperplastic prostatic tissue, thereby relieving theobstruction by removing the adenoma. Complications from TURP includebleeding, incontinence, retrograde ejaculation and impotence.

Examples of surgical devices for prostate tissue treatment are disclosedin U.S. Pat. Nos. 4,461,283; 5,672,171 and 5,630,794 and PCTInternational Publication Nos. WO 92/10142 and WO 93/15664 (the entirecontents of each of which are herein incorporated by reference).Examples of invasive techniques that surgically damage prostate tissueinclude laser treatments (including side firing, contact andinterstitial laser procedures), and transurethral ethanol ablation ofthe prostate (TEAP) as described in DiTrolio, J. V., TransurethralAblation of the Prostate, presented at the American UrologicalAssociation 94^(th) Annual Meeting, March 1999; and DiTrolio, J. V.,Chemoablation of the Prostate with Dehydrated Ethanol for Treatment ofBPH, 5th International Consultation on BPH, June 2000 in Paris, France(the entire contents of each of which are herein incorporated byreference). Examples of devices and methods for surgically damagingprostate tissue are disclosed in U.S. Pat. Nos. 5,322,503; 5,562,703;5,861,002; 6,231,591; and 6,461,296.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view showing the anatomical location ofprostate tissue.

FIG. 2 is a side view of a disassembled surgical instrument for use in apreferred embodiment of the present invention.

FIG. 3 is an enlarged side view of the surgical instrument of FIG. 2 inan assembled condition, that uses arrows to show the motion of elementsof the surgical instrument during deployment of a needle.

FIG. 4 is a side view showing a surgical kit according to another aspectof the present invention.

FIG. 5 is a view of another variation of the surgical instrumentaccording to the present invention.

FIG. 6 is a high pressure transurethral drug delivery embodiment of thepresent invention.

FIG. 7 is another variation of the embodiment of FIG. 6 to illustrate anadditional surgical instrument and method according to the presentinvention.

FIG. 8 is an enlarged view of a portion of FIG. 7.

FIG. 9 is a view of an additional feature of the surgical instrument andmethod according to the present invention.

FIG. 10 is a view of still another feature of the surgical instrumentand method according to the present invention.

FIG. 11 is a view of an arrangement to switch between ethanol and anechogenic agent useful in the practice of the present invention.

FIG. 12 a is a perspective view of an alternative embodiment of thesurgical instrument and method of the present invention.

FIG. 12 b is an enlarged view of a portion of FIG. 12 a.

FIG. 13 a is a view of an alternative embodiment of a surgicalinstrument in a first position according to the present invention.

FIG. 13 b is a view of the embodiment of FIG. 13 a in a second position.

FIG. 13 c is a perspective view corresponding to FIG. 13 a.

FIG. 13 d is an exploded view of the embodiment of FIG. 13 c.

FIG. 14 a is a view of an alternative embodiment of a surgicalinstrument in a first position according to the present invention.

FIG. 14 b is a view of the embodiment of FIG. 14 a in a second position.

FIG. 15 a is a view of an alternative embodiment of a surgicalinstrument in a first position according to the present invention.

FIG. 15 b is a view of the embodiment of FIG. 15 a in a second position.

FIG. 16 a is a view of a lockout arrangement according to an aspect ofthe present invention in a first, locked, position.

FIG. 16 b is a view of the lockout arrangement of FIG. 16 a in a second,unlocked, position.

FIG. 17 is a fragmentary view of the surgical instrument showing analternative embodiment of a locking mechanism useful in the practice ofthe present invention.

FIG. 18 a is fragmentary view of the surgical instrument showing analternative embodiment of a locking mechanism useful in the practice ofthe present invention.

FIG. 18 b is a detailed section view of a portion of FIG. 18 a.

FIG. 19 a is a fragmentary view of the surgical instrument showing astill further alternative embodiment of a locking mechanism useful inthe practice of the present invention.

FIG. 19 b is a plan view of the locking mechanism of FIG. 19 a.

FIG. 20 is a fragmentary section view of an alternative embodiment of ade-coupling mechanism useful in the practice of the present invention.

DETAILED DESCRIPTION

FIGS. 2 and 3 show an exemplary embodiment of surgical instrument 20 foruse in treating prostate tissue by injecting an effective amount of anactive ingredient (e.g. ethanol, acetic acid, phenol, Lidocaine, bulkingagents, botox, oxybutenin, carboxylic acid). FIG. 2 shows the device 20in an unassembled condition and FIG. 3 shows the device 20 in anassembled condition.

The device 20 includes a scope sheath 22 with eye port 21, a sheath 26and a main body with a needle deployment port 24, handle 30 and thumbring 34. The main body also includes an ethanol syringe port 32 that isdesigned to mate with a syringe 86. Preferably the syringe 86 has athreaded connector of the type commercially available from Becton,Dickinson and Company under the trade designation “Luer-Lok”, as opposedto a bayonet syringe or a non-threaded connector. Detents 28 areprovided for precise needle advancement through auditory, visual andtactile confirmation of needle-tip position in a lobe of the prostate.

The surgical device 20 is preferably sized and shaped for transurethralentry under direct vision. Optionally, a conventional cystoscope 27 andsheath 26 for transurethral entry under direct vision may be utilized asa portion of a kit 40. Alternatively, the device may be sized and shapedfor transrectal use. It is to be understood that kit 40 preferablyincludes device 20, syringe 86 and needle 76, and optionally includes areservoir 72 of ethanol or other therapeutically effective agent.

The assembled device 20 is advanced into the prostatic urethra. Thescope allows visual positioning of the needle port against the urethraadjacent to the lobe of the prostate to be treated. The needle isadvanced (as shown in the arrows in FIG. 3) one detent click at a time(e.g. 0.5 cm) to place the needle tip in the adenoma. A small volume(e.g. 3 to 5 ml) of an active ingredient such as anhydrous alcohol(ethanol) is slowly injected into the tissue. The urethral lumen may becontinuously irrigated while the ethanol is being administered.

The needle may then be withdrawn and the device 20 is removed from thesheath. The system may be rotated to target the next transurethralaccess point. An injection may be made to each lateral lobe of theprostate and in cases with median lobe enlargement, an injection may bemade to the median lobe of the prostate. In cases of longer prostaticurethra, a second plane of injections may optional be administered. Forexample, a total amount of about 13 ml may be the average amount ofethanol injected per patient.

The total dosage of ethanol will depend on a variety of factorsincluding, but not limited to the size of the prostate, the shape of theprostate (e.g. length and width), the number of injection sitesdetermined, and the nature and degree of prostate disease. The amount ofethanol could range from one or two mls to about 20 mls or more.

Optionally, the method may include other steps commensurate with thephysician's treatment strategy. Also optionally, other therapeuticallyeffective agents may be used with the surgical devices according to thepresent invention, including the substances described in U.S. patentapplication Ser. No. 10/193,716, filed Jul. 9, 2002 with the titleREGIMEN FOR TREATING PROSTATE TISSUE AND SURGICAL KIT FOR USE IN THEREGIMEN, the entire contents of which are hereby incorporated byreference.

In another embodiment, the ethanol may be combined with another agentthat enhances delivery and distribution of the ethanol within theprostate tissue. More preferably, the agent may more effectivelydisperse the ethanol in the vasculature of the prostate tissue. Forexample, the ethanol may be combined with GELFOAM® Sterile Powder,available from Pharmacia & Upjohn of Kalamazoo, Mich. The GELFOAM powderis believed to enhance the retention of the ethanol within the prostatetissue and to more effectively deliver the ethanol to the capillariesassociated with the prostate tissue. Alternatively, the ethanol may becombined with a means for enhancing visualization of the ethanol. Forexample, the agent may comprise a dye for enhancing visualization of theethanol. Better visualization of the ethanol may assist some surgeons inmore effectively delivering the ethanol to the prostate tissue andavoiding undesirable backflow.

In a preferred embodiment, the needle deployment port 24 is designed toafford a complete view of the entire needle at all points of deployment.

In another aspect, the present invention comprises the kit 40 fortreating a human male. The kit 40 may comprise a surgical kit. FIG. 4illustrates one example of a surgical kit 40 according to the presentinvention. The kit 40 includes a surgical device for damaging, treatingor therapeutically affecting prostate tissue according to the presentinvention.

The kit 40 includes the surgical device 20 described in conjunction withFIGS. 2 and 3. The device 20 includes a cystoscope 27 having a scopesheath 22 with eye port 21, a sheath 26 and a light cord connector 29.Device 20 also includes main body 31 with a needle deployment port 24,needle 25, handle 30 and thumb ring 34. The main body 31 also includesan ethanol syringe port 32 with a threaded Luer-Lok® feature. Detents 28are also provided.

Notably, the present invention is suitable for use in two pieceassemblies in contrast to the three piece assembly shown in FIG. 2. Forexample, the function of the sheath 26 and main body 31 could becombined into a unitary piece that is designed to operate in conjunctionwith endoscope 27. Also notably, the assembly may comprise a rigidassembly with, for example, a rigid sheath 26 and scope 27.Alternatively, the present invention includes embodiments that includeflexible assemblies, including, for example, flexible scopes 27 andflexible sheaths 26.

The kit 40 also includes a supply or reservoir 72 of a therapeuticallyeffective substance such as ethanol or a bulking agent. Needle 76 andsyringe 86 are provided to load the ethanol into syringe 86 fromreservoir 72. The syringe 86 may then be used to deliver ethanol 72through the needle 25 during a surgical procedure. Preferably, thedelivery is transurethrally. In operation, thumb ring 34 and handle 30are manually grasped and drawn together in the direction indicated byarrow 37, causing needle 25 to advance in the direction of arrow 39. Itis to be understood that the detents 28 may be used to stop advancementof needle 25 at predetermined distances set by the location of theindividual elements of the detents 28. Once the needle 25 is advanced tothe desired position within the prostate 10, syringe 86 is operated todeliver ethanol via needle 25 to the prostate 10, as desired. Whendelivery of ethanol is complete, thumb ring 34 is manually fullyretracted away from handle 30 in a direction opposite to arrow 37,causing needle 25 to retract into the needle deployment port 24 in adirection opposite to arrow 39.

In another embodiment, the thumb ring 34 may be biased toward theposition where the needle is fully retracted.

The elements of the kit may be packaged and sterilized together, or theymay be separately packaged and sterilized and assembled into a kit at alater date.

Referring to FIG. 5, a lockout release 42 can be added to the surgicalinstrument of FIGS. 2-4 to prevent premature deployment of the needle25. The lockout release 42 can be a button 44 which is spring loaded andwill automatically re-lock when the needle is retracted. When button 44is in the position shown in FIG. 5, button 44 will prevent advancementof the needle 25 via movement of a slide 45 because of interference withedge 46 of a frame 48 of the handle or finger grip 30 of a modifiedProstaject device 50. (Prostaject devices are available from AmericanMedical Systems, Inc. of Minnetonka, Minn., U.S.A..) There are a numberof possible ways to implement the concept, all involving the means toprevent or inhibit the relative motion between the handle/cystoscope andthe slide/needle. The means to prevent or inhibit this movement can beremoved by actuating a button when the physician is ready to advance theneedle. The button will re-set when the needle is retracted. Because theforce needed to insert the device transurethrally is in the samedirection as the force needed to advance the needle 25, there is achance that the needle 25 can be prematurely deployed, causing a hazardto the patient. This device (the lockout release 42) will prevent thisfrom happening. There are a variety of ways of implementing thisconcept, but all result in a structure that prevents or inhibitsmovement of the slide 45 relative to the front handle 30 and frame 48.

In another embodiment, a lockout assembly may be added to ethanolsyringe port 32 that prevents or inhibits advancement of the needle (byadvancing thumb ring 34) without a syringe 86 inserted in the syringeport 32. FIGS. 16 a and 16 b schematically illustrate a lockout releaseor assembly 42′ in both the locking and release positions. Although notshown in FIGS. 16 a and 16 b, it is to be understood that syringe 86 isa Luer-Lok® type syringe. In FIG. 16 a, the lockout assembly 42′ isshown in a blocking position where a first lockout arm or member 52 isurged in the direction of arrow 54 by a spring 56 acting against slide45. A second lockout arm or member 58 is connected to the first lockoutarm 52 at a pivot 60. A distal end 62 of member 58 engages a blockingtopology or notch 64 in an actuation member 66 which is operativelyassociated with the frame 48 and finger grip 30. In FIG. 16 a it may beseen that slide 45 is blocked (i.e., in a blocking condition) fromadvancing in the direction of arrow 68 by the interengagement of end 62and notch 64. In Figure 16 b, a release position or condition may beseen in which the syringe 86 urges first member 52 in the direction ofarrow 70 acting against spring 56 and causing member 58 to pivot againsta fixed point or fulcrum 74 in slide 45, moving in the direction ofarrow 78 to move distal end 62 out of engagement with member 66,allowing movement of slide 45 in the direction of arrow 68.

In another aspect, the present invention comprises a surgical instrumentthat includes a means to allow for visualization of a drug or the needleused to administer the drug that is injected into target tissue such asthe prostate gland. The invention can be divided into categories of waysto make the needle more visible on ultrasound and ways to make the fluiddelivered more visible.

Another aspect of the present invention is shown in FIGS. 6 through 8.In this aspect, the present invention comprises a method with the stepof injecting a drug into the prostate using a high-pressure needle-lessinjection system 80. A novel device 82 forms an aspect of the presentinvention and can operate independently or with a cystoscope 27 fortransurethral delivery of ethanol 84 into the prostate 10. Advantagesover a needle delivery system could include better depth of penetrationcontrol, containment within the prostate capsule, better volume delivery(minimize extravasation), faster procedure, less pain, and possiblebubble formation or bubble injection for visualization in TRUS(transrectal ultrasound). As an alternative, an echogenic substance canbe added to the ethanol to enable visualization during the procedure toassess penetration depth.

In FIG. 6, ethanol 84 is injected into the prostate 10 by high pressureneedle-less means 88, preferably in the form of an aperture 90delivering high pressure ethanol to a site adjacent the prostatetransurethrally. This would have the advantages mentioned over a needlesystem and would be expected to further include better depth of ethanolpenetration control. Optionally, a balloon may be used to press themeans 88 against urethral tissue to ensure suitable contact between themeans 88 and the urethral tissue.

FIG. 7 shows a variation of this approach in which a clear plastic orpolymer injection head 92 located adjacent a portion of the prostate 10.A high pressure fluid delivery tube 94 is connected to head 92.Borescope 22 is located within the cystoscope sheath 26 along with tube94. In operation, head 92 is positioned as desired using the borescope22 for visual observation while manipulating the sheath 26. A nozzle 100delivers high pressure ethanol 84, with echogenic bubbles 102, ifdesired. Optionally, a visually perceptible marker may be placed on orin the head 92 to indicate its position. A urethral balloon may also beused with this embodiment of the present invention.

Referring now also to FIG. 8, an enlarged view of the injection head 92may be seen. In this view, it may be seen that the nozzle 100 has afirst inlet 104 connected to tube 94 for delivering a chemical agentsuch as ethanol under high pressure. Nozzle 100 also has a second inlet106 connected to a gas delivery tube 108 for introducing pressurized gasto form bubbles 102 as an echogenic agent in the prostate tissue 10.

FIGS. 9 and 10 illustrate other aspects of the present invention. Theseaspects of the surgical instrument 20 include means to either limitinjection pressures to predetermined or desired levels during atransurethral ablation of the prostate (TEAP) procedure or features toindicate when unacceptably high pressures are reached.

FIG. 9 is a pressure limiter 110 for ethanol injection. A Luer-Lok® typesyringe 86 is connected to a housing 112 containing a pressure sensingdiaphragm 114, biased by a spring 116 to hold a shut-off valve 118 in anopen position as shown. An (optional) adjustment screw 120 may be usedto set the pressure at which valve 118 closes. The output 122 of thepressure limiter 110 is connected to the ethanol syringe port 32 of theProstaject device 50. The in-line pressure limiting valve can be used toprevent injection pressures from exceeding acceptable levels during TEAPprocedures. If pressures become excessive at the injection site,extravasation can result or rapid flow can occur along tissue planesthat allows the ethanol to miss the intended target. In operation, whenthe force resulting from pressure inside housing 112 in chamber 124exerted on diaphragm 114 exceeds the force resulting from spring 116,diaphragm 114 will move towards screw 120, closing valve 118. Valve 118will remain closed for as long as sufficient pressure exists in chamber126 to cause a force on valve 118 to remain closed against the force ofspring 116. Once the pressure in chamber 126 is reduced, the force fromspring 116 will open valve 118, and allow fluid to flow from chamber 126to chamber 124 and outlet 122.

Referring now to FIG. 10, a pressure indicator 130 may be seen.Indicator assembly 130 preferably has an inlet fitting 132 for receivinga Luer Lok® syringe 86 and an outlet fitting 134 for coupling to theLuer Lok® compatible ethanol syringe port 32 on an Prostaject device 50.It is to be understood that fittings 132 and 134 are shown in simplifiedform, without Luer Lok® details. Inlet and outlet fittings 132, 134 arepreferably formed integrally with a housing 136 which defines a passage137 connecting inlet 132 to outlet 134. Housing 136 further includes acylinder 138 carrying a piston 140 having an O-ring seal 142 sealing thepiston 140 against the cylinder 138. Piston 140 also has a rod or stem144 carrying a visually perceptible indicator or flag 146 at a distalend thereof. Indicator housing 136 also contains a spring 148 urgingpiston 140 to a retracted position, shown in solid lines in FIG. 10, inwhich flag 146 is concealed within housing 136. In operation, aspressures reach unacceptable levels (e.g., during a TEAP procedure), themoving rod 144 will extend, working against the preset force of spring148. The flag 146 will then extend beyond housing 134, and indicate tothe physician that pressures have exceeded acceptable levels. A groove139 extends part way along the cylinder 138 in housing 136 to allowfluid to bleed past the piston and O-ring seal 142 in the event apredetermined maximum pressure level is reached. The groove 139 beginsat a starting point 141 and extends a distance along the cylinder suchthat the liquid drug will leak past the piston 140 and O-ring seal 142via the groove 139 when a predetermined maximum pressure level isreached within the passage 137 causing the piston 140 to move againstthe spring 148 a distance sufficient to move the piston past thestarting point 141 of the groove 139.

FIGS. 11, 12 a and 12 b illustrate additional aspects of the surgicalinstrument and method according to the present invention. These aspectsinclude means for making the needle more visible including thefollowing. 1) The needle can be sandblasted to improve the ability toidentify its location via ultrasound. 2) The needle can have a thin filmconductor deposited over a dielectric for the purpose of operating aresistor for generating heat or a piezoelectric driver for generatingultrasonic vibration that could be detected via ultrasound imaging. Thedielectric capacitance and length of strip create a L-C monopole orbipolar antenna emitting a frequency spectrum to be picked up byexternal receiver and/or alternatively by ultrasound probe. 3) Echogenicmaterials could be injected after the needle is inserted into theprostate to verify needle position via TRUS. The ethanol (or other drug)could then be injected. The echogenic materials could includemicrospheres in a fluid medium, gas bubbles or solid particles suspendedin solutions. 4) The echogenic materials could be added to the drug andinjected simultaneously either through mixing them before injection orusing a double-barreled syringe and having them mix in the needle asseen in FIG. 11.

Notably, the surgical device may optionally include an ultrasonictransducer (e.g. on or near the needle), to enhance the dispersion ofthe injected substance within the tissue. In another embodiment, thesurgical needle may include a coating (e.g. on the needle) of Echo-Coat®material (available from STS Biopolymers Inc.) for better visualizationand control.

FIG. 11 shows a simplified view of an ethanol injection visualization150 with a number of parts of the surgical instrument 20 omitted forsimplicity. In this visualization, a cannula 152 is connected to amanual device or valve 154 for switching between an echogenic agent andthe ethanol. One or more sand blasted surfaces in the form of bands 156,158 are located at a distal end 160 of the cannula 152 in order toidentify the needle tip and/or the location of injection of ethanol intothe prostate 10. Several means can be employed: 1) The drawing of FIG.11 shows a two-syringe system that could inject an agent visible onultrasound first using the echogenic agent syringe 157, then inject theethanol using the ethanol syringe 86 after the position has beenidentified. The echogenic agent could include microspheres, solidparticles in suspension, bubbles, fluids different in density fromwater, etc. 2) The needle itself can be modified to have bettervisualization on ultrasound. One way to accomplish this is to roughenthe surface of the needle using sandblasting (as shown in FIG. 11) orother means, as illustrated in FIG. 12 b.

FIGS. 12 a and 12 b show further ethanol injection visualizations 162,164. FIG. 12 a illustrates a means to inject a drug (ethanol) incombination with an echogenic marker or radio-opaque markersimultaneously using a Y-connection 166 where the fluids mix, comingfrom a first tube 168 having a lumen 170 carrying the ethanol and asecond tube 172 having a lumen 174 carrying the echogenic agent, both ofwhich are connected via the Y-connection 166 to the cannula 152. FIG. 12b illustrates an alternative embodiment of cannula 152 having first andsecond thin film conductors 176, 178 connected near the distal end 160of cannula 152 to a resistor 180 or thin film/MEMS to produce atemperature signal or a piezo oscillator to produce an ultrasonicbeacon.

FIGS. 13 a through 15 b are views of additional embodiments of surgicalinstruments and methods according to the present invention. Theseembodiments have a mechanism for raising the needle 25 in aperpendicular or substantially perpendicular fashion relative to thesides of a needle deployment port. Optionally, an infrared or otherlight spot may be projected perpendicular to the sheath to the locationin the body that would receive the needle. This feature would allow thesurgeon to presight or target the specific tissue to be treated.

FIGS. 13 a, 13 b, 13 c, 13 d, 14 a, 14 b, 15 a and 15 b show variousembodiments of the present invention which have structure for raisingthe needle in perpendicular or substantially perpendicular direction tothe longitudinal axis of the device. Moving the needle in this fashionis believed to provide better control over placement of the needle andthus, the injectable substance. Assemblies for raising a structure in adirection that is perpendicular or substantially perpendicular to thelongitudinal axis of a surgical device are described in U.S. Pat. No.5,306,284 to Agee et al., the contents of which are incorporated hereinby reference.

FIGS. 13 a and 13 b illustrate an embodiment having needle 182 operatedby a pusher 184, which moves in the direction of arrow 186 to raise theneedle 182 along path 183 and in the general direction of arrow 185.FIG. 13 c is a perspective view corresponding to FIG. 13 a, and FIG. 13d is an exploded view of this embodiment. It is to be understood thatone or more trunnions 188 project out from needle 182 without blockingor providing a leak path with respect to the lumen 190 interior ofneedle 182. In FIGS. 13 c and 13 d it is to be understood that pivot pin189 is secured to a housing 191 of the assembly. In FIG. 13 c the needle182 is guided by a slot 187 to avoid urethral damage that mightotherwise occur due to excessive needle displacement. Furthermore, sucha slot guide is expected to reduce the potential for high backflow dueto low resistance with an enlarged opening that could reduce theeffectiveness of the treatment using the apparatus or method of thepresent invention. FIGS. 14 a and 14 b illustrate another embodimenthaving needle 182 operated by pusher 184, with at least two trunnions188 on needle 182. Pusher 184 is moved in the direction of arrow 186 toraise needle 182 generally in the direction of arrow 185. FIGS. 15 a and15 b illustrate still another embodiment having needle 182 operated bypusher 184 via trunnion 188 on needle 182. Pusher 184 is pushed in thedirection of arrow 186 to raise needle 182 generally in the direction ofarrow 185. In this embodiment, a plate 192 having a curved slot 194 isfastened to needle 182 by conventional means such as welding 196. Slot194 acts against a roller 196 secured to housing 198 to cause needle 182to move in response to movement of pusher 184.

Referring now to FIG. 17, a still further variation of a lockout release42 may be seen. In this variation, a loose pin 200 (preferably retainedby a tether 202) is inserted manually into one of a plurality of pairsof through apertures 204 present for the detents 28 in the Prostajectdevice 50. Placing the pin 200 in an aligned aperture pair 204 preventsadvancement of the slide 45 associated with thumb ring 34 past a desireddetent position with respect to frame 48 associated with handle 30, andthus prevents over advancing needle 25 from the needle deployment port24. It is to be understood that FIG. 17 shows pin 200 in both aninstalled position in aperture 204, and in a free position, with thetether indicated by dashed line 206 in the free position. It is to befurther understood that the apertures corresponding to predetermineddistances the needle may be extended correspond to the various detentpositions. In operation, the slide will be released to advance until anedge of the structure of the slide contacts the pin in one of theapertures 204, limiting the movement of the slide with respect to theframe, as desired. A further variation of this approach is to provide anaperture which prevents any extension of the needle with the pinreceived in the aligned aperture pair, with one aperture in the slideand the other aperture in the frame.

FIG. 18 a is a fragmentary view and FIG. 18 b is a partial section view(along line 18 b-18 b of FIG. 18 a) of yet another variation of thelockout release 42. In this variation, each detent 28 is surrounded by agenerally spherical recess 208. In this variation, a ball 210 of thedetent 28 projects sufficiently far out of a recess 212 in slide 45 toblock transverse movement of slide 45 with respect to frame 48. When itis desired to permit transverse movement of slide 45 with respect toframe 48 (to advance or retract needle 25) ball 210 is manuallydepressed into recess 212 by engagement of an operator's finger in thespherical recess 208. A spring 214 urges ball 210 away from recess 212.It is to be understood that the frame 48 of the handle 30 of theProstaject device 50 currently has the ball 210 that fit into the holes204 to indicate position and act as detents 28 because the ball 210 onlyrests partially in one of holes 204. This currently gives slightresistance to movement. If the ball 210 and hole diameter are sized togive a positive lock, that cannot be overcome by just the pressure onthe thumb ring 34 pushing the slide 45 forward toward the handle 30. inone form of this variation, only the back hole 216 can be made such thata finger of the operator's hand can push the ball 210 in and release thelock in the hole 216, while the other holes 204 can be sized to giveonly slight interference.

Referring now to FIGS. 19 a and 19 b, a stepped cam version of thelockout release 42 is shown. In this version a stepped cam 218 islocated for rotational movement on the projection 220 that carries theethanol syringe port 32. The stepped cam 218 is in the form of a diskhaving steps 222, 224, 226, and 228 with different radii and individualindices, represented by the letters “A” “B” “C” and “D.” It is to beunderstood that the projection 220 moves forward to the top fingersupport 230 where the cam 218 will hold the slide and frame apart by thedistance set by the respective radius selected on cam 218 to bepositioned between the projection 220 and finger support 230. Inoperation, when the physician is ready to advance the needle 25 out fromport 24, he or she would rotate the disk 218 to a position that allowsthe needle 25 to be advanced to a predetermined distance. The physicianwould then advance the thumb ring 34 toward handle 30, moving needle 25forward until the selected step on disk 218 bottoms out against fingersupport 230. It is to be understood that the indices associated with thesteps preferably indicate the respective distances of advance for theneedle 25.

Referring now to FIG. 20, a de-coupling mechanism useful in the practiceof the present invention may be seen. In this version, a switch 242provides for de-coupling a handle 240 from the needle 25 to preventunwanted needle extension instead of blocking relative movement of thetwo members as described for the embodiment of, e.g., FIG. 5. Thisallows the handle 240 to slide back and forth without movement of theneedle until the switch or button 242 is pushed (or other actuation isused) that re-couples the handle 240 to the needle 25 and then allowsthe needle 25 to be advanced with the handle 240. Specifically, in FIG.20, the handle 240 (corresponding to thumb ring 34) is able to moverelative to the needle 25 without button 242 being pushed. When button242 is pushed, the handle 240 is mechanically connected to the needle 25to advance and retract the needle, by movement of the handle 240 withrespect to handle or finger grip 30. It may thus be seen that theembodiment of FIG. 20 provides selective coupling apparatus for asurgical instrument of the type having an remotely controllableextendable and retractable needle. The selective coupling apparatusincludes a mechanism for selectively engaging and releasing first andsecond members (such as handles 240 and 30) from moving with respect toeach other. The mechanism provides a mechanical connection between thefirst and second members when in an operating condition (when button 242is pushed) and the mechanism provides clearance between the first andsecond members when in a de-coupled condition (when button 242 isreleased).

In describing preferred embodiments of the invention, specificterminology is used for the sake of clarity. The invention, however, isnot intended to be limited to the specific terms so selected, and it isto be understood that each term so selected includes all technicalequivalents that operate similarly.

These and other advantages of the invention are more fully shown anddescribed in the drawings and detailed description of this invention,where like reference numerals are used to represent similar parts. It isto be understood, however, that the drawings and description are for thepurposes of illustration only and should not be read in a manner thatwould unduly limit the scope of this invention. This invention may takeon various modifications and alterations without departing from thespirit and scope thereof

1. A method of extending a needle from a surgical instrument forinjecting a liquid drug into a prostate, the method comprising:providing a link assembly at a distal end of the surgical instrumentwith the link assembly connected to a needle and to a housing carryingthe needle; and extending the needle generally transversely to thehousing using a pusher moving longitudinally in the housing actingthrough the link assembly.
 2. The method of claim 1 wherein the step ofextending the needle further comprises pivoting the link assembly abouta pivot connected to the housing.
 3. The method of claim 1 wherein thestep of extending the needle further comprises pivoting the needle usingat least one link arm pivotally connected to the housing.
 4. The methodof claim 1 wherein the step of extending the needle further comprisesmoving the needle using a slot moving along a pin connected to thehousing.
 5. The method of claim 1 wherein the step of extending theneedle further comprises guiding the needle through a slot in thehousing.